| 초록 |
We developed a ratiometric pH sensor based on poly(N-phenylmaleimide) (PPMI) which exhibits tricolor luminescence with subject to pH changes. PPMI and its derivatives showed strong solvatochromism and tautomerism enabling precise pH sensing by emission color changes from green to yellow and yellow to orange at pH values of 4.5 and 9.5, respectively. These were originated from not only the changes in emission wavelength but also alterations in fluorescence intensities. Computational prediction proves dissimilar band gaps for keto, enol, and enolate tautomers of PPMI owing to the low dimensional conjugation effect. Block copolymerization of fluorescent PPMI with water soluble poly(ethylene oxide) (PEO) units offers good water solubility. In particular, the self-assembly nature of the synthesized PPMI-b-PEO block copolymer in aqueous media leads to an easy processability into diverse device forms such as solutions, thin films, and membranes with non-significant self-quenching behavior. |
